We have found that a black sorbent thermoset foam can be prepared by the pyrolysis of a liquid composition comprising at least one aromatic nitrogen-containing compound. Such foams are described in our copending Patent Application Nos. 25181/73, and 25182/73 and are found to have excellent sorption for polar molecules. When prepared as described in these applications, the sorbent foams tend to be in the form of a fine black powder having a low bulk density. This can make it difficult to handle the foams and to retain them during their use as sorbents.
Similar problems can be experienced with active carbon and it has been the practice to blend active carbon particles with a binder and then to granulate and carbonise the mixture. In this way, hard attrition resistant granules can be prepared which can be easily handled and used without significant loss in the absorbtive capacity of the active carbon. Sorbent thermoset foams as described above cannot be granulated easily in this way without significant decrease in the valuable chemisorption capacity of the foams occuring during sintering.
It is, therefore, an object of this invention to provide a way of incorporating these sorbent thermoset foams into a carrier without substantial loss of the specific surface area and sorptive capacity of the foams.